head to head
Neither is simply harder - they are hard in different places. Grand Theft Auto: San Andreas demands more optimization; James Bond 007: Agent Under Fire demands more execution.

Optimization · Practiced Mastery
A sprawling open-world crime epic with RPG-style character stats across a whole state.

Execution · Practiced Mastery
A spy shooter testing console aim and learning each mission's intended route.
Grand Theft Auto: San Andreas leans Optimization (Practiced Mastery); James Bond 007: Agent Under Fire leans Execution (Practiced Mastery).
James Bond 007: Agent Under Fire leans clearly harder on execution.
Grand Theft Auto: San Andreas
Flying school and drive-bys need decent hands
James Bond 007: Agent Under Fire
Console FPS aim and rail-shooter timing carry missions
James Bond 007: Agent Under Fire leans a little harder on reads, though the gap is small.
Grand Theft Auto: San Andreas
Gang AI is scripted, never adaptive
James Bond 007: Agent Under Fire
Split-screen friends add mild prediction; campaign AI is scripted
Grand Theft Auto: San Andreas leans a little harder on variance, though the gap is small.
Grand Theft Auto: San Andreas
Territory wars and traffic add light randomness
James Bond 007: Agent Under Fire
Missions play out identically each attempt
Grand Theft Auto: San Andreas leans clearly harder on optimization.
Grand Theft Auto: San Andreas
Stats, gym, weapon skill, and routes reward systematic play
James Bond 007: Agent Under Fire
Gadget usage and stealth routes raise mission ratings
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.